4. We must "go on toward perfection"; for if we fall away, after having received enlightenment, it will be impossible to renew us again to repentance.
      for those--"in the case of those."
      once enlightened--once for all illuminated by the word of God taught in connection with "baptism" (to which, in Heb 6:2, as once for all done," once enlightened" here answers); compare Eph 5:26. This passage probably originated the application of the term "illumination" to baptism in subsequent times. Illumination, however, was not supposed to be the inseparable accompaniment of baptism: thus CHRYSOSTOM says, "Heretics have baptism, not illumination: they are baptized in body, but not enlightened in soul: as Simon Magus was baptized, but not illuminated." That "enlightened" here means knowledge of the word of truth, appears from comparing the same Greek word "illuminated," Heb 10:32, with Heb 10:26, where "knowledge of the truth" answers to it.
      tasted of the heavenly gift--tasted for themselves. As "enlightened" refers to the sense of sight: so here taste follows. "The heavenly gift"; Christ given by the Father and revealed by the enlightening word preached and written: as conferring peace in the remission of sins; and as the Bestower of the gift of the Holy Spirit (Ac 8:19, 20),
      made partakers of the Holy Ghost--specified as distinct from, though so inseparably connected with, "enlightened," and "tasted of the heavenly gift," Christ, as answering to "laying on of hands" after baptism, which was then generally accompanied with the impartation of the Holy Ghost in miraculous gifts.

JFB.